THURSDAY, Jan. 15, 2026 (HealthDay News) -- An elevated neutrophil-to-lymphocyte ratio (NLR) is associated with a higher prevalence of depressive disorder (DD) and with increased suicide risk among those with DD, according to a review published in the November/December issue of the Harvard Review of Psychiatry.Yuanyuan Zhou, from the Institute of Acupuncture and Moxibustion in Jinan, China, and colleagues conducted a systematic literature review to identify studies assessing the relationship between NLR and DD. The primary outcome was the prevalence of DD and suicide risk in individuals with DD.The review included 37 studies, with 88,019 participants. The researchers found that high NLR was significantly associated with DD presence (odds ratio, 1.57). Individuals diagnosed with DD had elevated NLR levels in continuous analyses (standardized mean difference, 0.73). In addition, heightened suicide risk was seen among those with DD in association with increased NLR (categorical outcome odds ratio, 1.56; continuous outcome standardized mean difference, 0.42)."These findings underscore the clinical relevance of systemic inflammation in DD pathophysiology and highlight NLR as a cost-effective, accessible tool to inform risk stratification and tailored treatment strategies in psychiatric care," the authors write.Abstract/Full Text (subscription or payment may be required).Sign up for our weekly HealthDay newsletter